基于离散单元法墙体平面外受力性能分析

发布时间：2018-03-20 03:30

本文选题：离散单元法　切入点：平面外受力性能　出处：《武汉理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：在地震或者风荷载作用下,墙体的面外刚度不足往往引起墙体面外倒塌,造成人员伤亡和财产损失,因此墙体的面外受力性能研究显得格外重要。由于墙体是由块体和砂浆两相材料组砌而成,材料性能差异较大,墙体的非均质性导致其受力性能极其复杂,在进行非线性分析时往往会出现破坏准则定义困难、收敛速度慢、甚至不收敛等问题,通常的处理方式是将块体与砂浆进行均质化(RVE),而这也只是一种粗略的近似,适用于宏观模型的力学分析,对于单片墙体需要更精细化的方式处理,此时应考虑块体与砂浆之间的相互作用以及材料差异引起的影响。岩体中的结构面为岩体的“薄弱层”,这与砌体结构的砂浆层相似,砌体结构的砂浆层、砂浆与块体之间的接触面是砌体最容易产生破坏的位置。本文借鉴分析岩石力学的方法分析砌体结构,对砂浆和块体采取分离式建模,砂浆与块体之间的接触面采用岩石中的“节理面”模拟,基于离散单元法,针对墙体平面外受力性能,开展了如下三个方面的工作:1)基于离散单元法模拟分析阿德莱德大学Griffith教授关于无筋墙体力学性能试验中的Wall1和Wall3墙体,通过对比数值分析结果与试验结果,验证了建模方法、材料参数定义、破坏准则定义的合理性,为后面定性地分析各参数对砌体墙平面外受力性能影响分析提供依据。2)研究墙体的几何参数、边界条件对砌体墙平面外受力性能的影响,建立了不同高厚比、竖向压力以及高宽比数值模型,分析了各种参数对墙体面外性能的影响规律,得到了不同高宽比、高厚比以及不同竖向压力墙体的极限荷载和破坏模式。3)对配筋墙体进行数值模拟分析,对比分析了无筋墙体与配筋墙体承载力、延性、破坏模式的不同以及钢筋对配筋墙体的作用机理;模拟了不同配筋率、不同配筋方式对墙体承载力、开裂荷载及破坏过程的影响,提出了墙体的合理配筋率以及最优配筋方式。
[Abstract]:Under the action of earthquake or wind load, the lack of out-of-plane stiffness of the wall often causes the out-of-plane collapse of the wall, resulting in casualties and property losses. Therefore, it is very important to study the out-of-plane mechanical properties of the wall. Because the wall is made of block and mortar two-phase materials, the material performance is different, and the heterogeneity of the wall makes its mechanical performance extremely complex. In nonlinear analysis, the failure criterion is difficult to define, the convergence rate is slow, and even does not converge. The usual treatment is to homogenize the block and mortar, but this is only a rough approximation. For the mechanical analysis of macroscopic model, the monolithic wall needs to be treated in a more detailed way. The interaction between block and mortar and the influence caused by material difference should be considered. The structural plane in rock mass is the "weak layer" of rock mass, which is similar to the mortar layer of masonry structure, and the mortar layer of masonry structure. The contact surface between mortar and block is the most easily damaged position of masonry. In this paper, the masonry structure is analyzed by using the method of rock mechanics, and the mortar and block are modeled separately. The interface between mortar and block is simulated by "joint surface" in rock. Based on the discrete element method, the mechanical behavior of the wall outside the plane is analyzed. The following three aspects of work were carried out: 1) based on discrete element method, the Wall1 and Wall3 walls in mechanical performance tests of unstiffened walls were simulated and analyzed by Professor Griffith of the University of Adelaide. The modeling method was verified by comparing the results of numerical analysis with the experimental results. The definition of material parameters and failure criteria is reasonable, which provides a basis for the qualitative analysis of the influence of each parameter on the mechanical behavior of masonry wall outside the plane. 2) the geometric parameters of the wall are studied. The influence of boundary conditions on the behavior of the masonry wall outside the plane is studied. The numerical models of different height-thickness ratio, vertical pressure and aspect ratio are established, and the influence of various parameters on the out-of-plane performance of masonry wall is analyzed, and the ratio of height to width is obtained. The ratio of height to thickness and the ultimate load and failure mode of different vertical pressure wall are analyzed by numerical simulation, and the bearing capacity and ductility of the reinforced wall and the reinforced wall are compared and analyzed. Different failure modes and the action mechanism of reinforcement on reinforced wall are simulated, and the effects of different reinforcement ratio and different reinforcement ways on the bearing capacity, cracking load and failure process of the wall are simulated, and the reasonable reinforcement ratio and the optimal reinforcement mode of the wall are put forward.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU364

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